Water and Air Sample Data Documentation

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Water and Air Sample Data Documentation

Introduction

During OMEX I the daunting total of 478 different parameters were measured on water or air samples by 48 principal investigators using a wide range of protocols. The aim of this document is to allow the protocol used to obtain any particular data value within the BOTDATA table to be determined with ease.

To help you find the information you require quickly, the document is subdivided into sections that describe groups of closely related parameters.

These are listed below as a series of hot links. Each section starts with the definition of the parameter codes covered, followed by a list of who measured one or more of those parameters by cruise. Next, there is a protocol section describing the methods used by each principal investigator. Finally, there may be comments on data quality that have been noted by BODC or have come to our attention.

<TIP> If you want to find out a how a particular parameter was measured and know the parameter code then the fastest way to find the information you require is to use the Acrobat 'find' tool to search for the parameter code. Then use the 'find' tool again to search for the name of the principal investigator. This will take you straight to the protocol description you require.

Parent Home

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Document Index

Carbon, Nitrogen and Phosphorus Assimilation

Data from ¹⁴C, ¹⁵N and ³²P short duration uptake experiments where the results having been expressed in terms of uptake per hour, together with parameterised PvI data (alpha and Pmax).

Metal Assimilation Rates

Data from assimilation experiments using gamma-emitting isotopes of trace metals.

Metal Distribution Coefficients

Trace metal distribution coefficients between the dissolved and particulate phases measured using gamma-emitting isotopes.

Bacterial Production, Abundance and Characteristics

Bacterial abundance, biomass and size data plus thymidine and leucine uptake data.

Carbon and Nitrogen Isotopes

Carbon isotope data on dissolved inorganic carbon plus carbon and nitrogen data on particulate organic matter.

Dissolved and Colloidal Organic Carbon

High temperature catalytic oxidation measurements.

Dissolved Total Nitrogen and Phosphorus

Provide the basis for the determination of dissolved organic nitrogen and phosphorus for samples that have nutrient data.

Particulate Organic Carbon, Inorganic Carbon, Nitrogen, Phosphorus and Silica

The parameters often loosely described as 'POC' and 'PON' plus inorganic carbon, phosphorus and biogenic (opaline) silica data.

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Nutrients

Nitrate plus nitrite, nitrite, phosphate, silicate, ammonia and urea data.

Dissolved and Particulate Carbohydrates

Total carbohydrate in the dissolved and particulate phases.

Amino Acids and Fatty Acids

Total free amino acids plus some seventy individual fatty acids.

Carbonate System Parameters

Dissolved total inorganic carbon, pCO2 in water and the atmosphere, alkalinity and pH.

Dissolved and Colloidal Trace Metals

Aluminium, cadmium, cobalt, copper, total iron, total manganese, nickel, lead and zinc data.

Particulate Trace Metals

Aluminium, calcium, cadmium, cobalt, chromium, copper, total iron, potassium, lithium, magnesium, total manganese, sodium, nickel, lead, silicon and zinc contents of suspended particulate material.

Pigments

Chlorophyll-a determined by a range of techniques, including data derived from calibrated in-situ fluorometers, plus a full suite of pigments determined by HPLC.

Suspended Particulate Material Concentration and Characterisation

Gravimetric SPM determinations plus some particle size data.

Dimethylsulphide and its Precursors

Dimethylsulphide plus DMSP and DMSO.

Carbonyl Sulphide.

Atmospheric concentrations, seawater concentrations and production data.

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Methane

Dissolved and atmospheric methane data.

Atmospheric Ammonia and Methylamines

Gaseous and particulate atmospheric data.

Dissolved Methylamines

Monomethylamine, dimethylamine and trimethylamine concentrations.

Dissolved Oxygen

Dissolved oxygen concentrations including data derived from calibrated in- situ oxygen probe data.

Hydrography

Temperature, salinity, density and attenuance data that have largely been derived from CTD data together with calibration bottle salinity and reversing thermometer data.

Irradiance

Light meter data at bottle firing depths.

Volume of Water Filtered

Records of the volume of water sampled by stand-alone pumps and underway centrifuges.

Microzooplankton Biomass and Grazing

Microzooplankton abundance, biomass and grazing together with data on heterotrophic and photosynthetic nanoflagellates.

Phytoplankton Species Counts

Abundance of phytoplankton taxa.

Zooplankton and Terrestrial Detritus

Zooplankton abundance by taxonomic group together with pollen and fungal detritus counts.

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Radionuclides

Plutonium, barium, strontium and americium isotope data.

Atmospheric Radon

Determinations of radon through monitoring of its decay products.

Current Parameters

Parameterised data from current meters attached to a benthic water sampling system.

References

Full references for the papers cited in the protocol descriptions.

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Carbon, Nitrogen and Phosphorus Assimilation

Parameter Code Definitions

ALPHPIP1 Quantum yield (alpha)

PvI incubation (GF/F filtered) mg C/(µE/m²/s)/mg chl/hour

NAUPRAP1 Normalised ammonium uptake (100 µE/m²/s)

Tracer-doped constant light incubation at 100 µE/m²/s (GF/F filtered)

Nanomoles per litre per hour

NAUPRBP1 Normalised ammonium uptake (188 µE/m²/s)

NAUPRDP1 Normalised ammonium uptake (dark)

Tracer-doped incubation in darkness (GF/F filtered) Nanomoles per litre per hour

NAUPRSP1 Normalised ammonium uptake (natural light)

Tracer-doped incubation in natural sunlight (GF/F filtered) Nanomoles per litre per hour

NCUPRAP1 Normalised carbon uptake (100 µE/m²/s)

Radiotracer doped constant light incubation at 100 µE/m²/s (GF/F filtered)

Milligrams/metre cube/hour

NCUPRAP4 Normalised carbon uptake (100 µE/m²/s)

Radiotracer doped constant light incubation at 100 µE/m²/s (sum size fractions >0.2 microns)

NCUPRBP1 Normalised carbon uptake (188 µE/m²/s)

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NCUPRBP4 Normalised carbon uptake (188 µE/m²/s)

Milligrams/metre cube/hour NCUPRDP1 Normalised carbon uptake (dark)

Radiotracer doped incubation in the dark (GF/F filtered) Milligrams/metre cube/hour

NCUPRDP4 Normalised carbon uptake (dark)

Radiotracer doped incubation in the dark (sum size fractions

>0.2 microns)

NCUPRPP1 Normalised carbon uptake (azide control)

Radiotracer doped azide poisoned control incubation (GF/F filtered)

NCUPRPP4 Normalised carbon uptake (azide control)

Radiotracer doped azide poisoned control incubation (sum size fractions >0.2 microns)

NCUPRSP1 Normalised carbon uptake (natural light)

Radiotracer doped incubation in natural sunlight (GF/F filtered) Milligrams/metre cube/hour

NCUPRSP4 Normalised carbon uptake (natural light)

Radiotracer doped incubation in natural sunlight (sum size fractions >0.2 microns)

NCUPRZP1 Normalised carbon uptake (188 µE/m²/s with antibiotic)

Radiotracer doped constant light incubation at 188 µE/m²/s with antibiotic (GF/F filtered)

NCUPRZP4 Normalised carbon uptake (188 µE/m²/s with antibiotic)

Radiotracer doped constant light incubation at 188 µE/m²/s with antibiotic (sum size fractions >0.2 microns)

NNUPRAP1 Normalised nitrate uptake (100 µE/m²/s)

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NNUPRBP1 Normalised nitrate uptake (188 µE/m²/s)

Nanomoles per litre per hour NNUPRDP1 Normalised nitrate uptake (dark)

Tracer-doped incubation in darkness (GF/F filtered) Nanomoles per litre per hour

NNUPRSP1 Normalised nitrate uptake (natural light)

Tracer-doped incubation in natural sunlight (GF/F filtered) Nanomoles per litre per hour

NPUPRAP1 Normalised phosphorus uptake (100 µE/m²/s)

NPUPRAP4 Normalised phosphorus uptake (100 µE/m²/s)

NPUPRBP1 Normalised phosphorus uptake (188 µE/m²/s)

NPUPRBP4 Normalised phosphorus uptake (188 µE/m²/s)

NPUPRDP1 Normalised phosphorus uptake (dark)

Radiotracer doped incubation in the dark (GF/F filtered) Nanomoles per litre per hour

NPUPRDP4 Normalised phosphorus uptake (dark)

Radiotracer doped incubation in the dark (sum size fractions

>0.2 microns)

NPUPRPP1 Normalised phosphorus uptake (azide control)

Radiotracer doped azide poisoned control incubation (GF/F filtered)

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NPUPRPP4 Normalised phosphorus uptake (azide control)

Radiotracer doped azide poisoned control incubation (sum size fractions >0.2 microns)

NPUPRSP1 Normalised phosphorus uptake (natural light)

Radiotracer doped incubation in natural sunlight (GF/F filtered) Nanomoles per litre per hour

NPUPRSP4 Normalised phosphorus uptake (natural light)

Radiotracer doped incubation in natural sunlight (sum size fractions >0.2 microns)

NPUPRXP4 Normalised phosphorus uptake (100 µE/m²/s with antibiotic) Radiotracer doped constant light incubation at 100 µE/m²/s (sum size fractions >0.2 microns)

NPUPRYP1 Normalised phosphorus uptake (dark with antibiotic)

Radiotracer doped incubation in the dark with antibiotic (GF/F filtered)

NPUPRYP4 Normalised phosphorus uptake (dark with antibiotic)

Radiotracer doped incubation in the dark with antibiotic (sum size fractions >0.2 microns)

NPUPRZP1 Normalised phosphorus uptake (188 µE/m²/s with antibiotic) Radiotracer doped constant light incubation at 188 µE/m²/s (GF/F filtered)

NPUPRZP4 Normalised phosphorus uptake (188 µE/m²/s with antibiotic) Radiotracer doped constant light incubation at 188 µE/m²/s (sum size fractions >0.2 microns)

NUUPRBP1 Normalised urea uptake (188 µE/m²/s)

Nanomoles per litre per hour PMAXPIP1 Photosynthetic maximum (Pmax)

PvI incubation (GF/F filtered) mg C/mg chl/hour

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SNAURSPM Size-fractionated normalised ammonium uptake (natural light) Tracer doped incubation in natural sunlight (GF/F- 5µm size fraction)

SNCURAPB Size-fractionated normalised carbon uptake (100 µE/m²/s) Radiotracer doped constant light incubation at 100 µE/m²/s (>2µm size fraction)

SNCURAPF Size-fractionated normalised carbon uptake (100 µE/m²/s) Radiotracer doped constant light incubation at 100 µE/m²/s (0.2-2µm size fraction)

SNCURBPB Size-fractionated normalised carbon uptake (188 µE/m²/s) Radiotracer doped constant light incubation at 188 µE/m²/s (>2µm size fraction)

SNCURBPF Size-fractionated normalised carbon uptake (188 µE/m²/s) Radiotracer doped constant light incubation at 188 µE/m²/s (0.2-2µm size fraction)

SNCURDPB Size-fractionated normalised carbon uptake (dark)

Radiotracer doped incubation in the dark (>2µm size fraction) Milligrams/metre cube/hour

SNCURDPF Size-fractionated normalised carbon uptake (dark)

Radiotracer doped incubation in the dark (0.2-2µm size fraction) Milligrams/metre cube/hour

SNCURPPB Size-fractionated normalised carbon uptake (azide control) Radiotracer doped azide poisoned control incubation (>2µm size fraction)

SNCURPPF Size-fractionated normalised carbon uptake (azide control) Radiotracer doped azide poisoned control incubation (0.2-2µm size fraction)

SNCURSPB Size-fractionated normalised carbon uptake (natural light) Radiotracer doped incubation in natural sunlight (>2µm size fraction)

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SNCURSPF Size-fractionated normalised carbon uptake (natural light) Radiotracer doped incubation in natural sunlight (0.2-2µm size fraction)

SNCURZPB Size-fractionated normalised carbon uptake (188 µE/m²/s with antibiotic)

Radiotracer doped incubation at 188 µE/m²/s with antibiotic (>2µm size fraction)

SNCURZPF Size-fractionated normalised carbon uptake (188 µE/m²/s with antibiotic)

Radiotracer doped incubation at 188 µE/m²/s with antibiotic (0.2-2µm size fraction)

SNNURSPM Size-fractionated normalised nitrate uptake (natural light) Tracer doped incubation in natural sunlight (GF/F- 5µm size fraction)

SNPURAPB Size-fractionated normalised phosphorus uptake (100 µE/m²/s) Radiotracer doped constant light incubation at 100 µE/m²/s (>2µm size fraction)

SNPURAPF Size-fractionated normalised phosphorus uptake (100 µE/m²/s) Radiotracer doped constant light incubation at 100 µE/m²/s (0.2-2µm size fraction)

SNPURBPB Size-fractionated normalised phosphorus uptake (188 µE/m²/s) Radiotracer doped constant light incubation at 188 µE/m²/s (>2µm size fraction)

SNPURBPF Size-fractionated normalised phosphorus uptake (188 µE/m²/s) Radiotracer doped constant light incubation at 188 µE/m²/s (0.2-2µm size fraction)

SNPURDPB Size-fractionated normalised phosphorus uptake (dark)

Radiotracer doped incubation in the dark (>2µm size fraction) Nanomoles per litre per hour

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SNPURDPF Size-fractionated normalised phosphorus uptake (dark)

Radiotracer doped incubation in the dark (0.2-2µm size fraction) Nanomoles per litre per hour

SNPURPPB Size-fractionated normalised phosphorus uptake (azide control) Radiotracer doped azide poisoned control incubation (>2µm size fraction)

SNPURPPF Size-fractionated normalised phosphorus uptake (azide control) Radiotracer doped azide poisoned control incubation (0.2-2µm size fraction)

SNPURSPB Size-fractionated normalised phosphorus uptake (natural light) Radiotracer doped incubation in natural sunlight (>2µm size fraction)

SNPURSPF Size-fractionated normalised phosphorus uptake (natural light) Radiotracer doped incubation in natural sunlight (0.2-2µm size fraction)

SNPURXPB Size-fractionated normalised phosphorus uptake (100 µE/m²/s with antibiotic)

SNPURXPF Size-fractionated normalised phosphorus uptake (100 µE/m²/s with antibiotic)

Radiotracer doped incubation at 100 µE/m²/s with antibiotic(0.2- 2µm size fraction)

SNPURYPB Size-fractionated normalised phosphorus uptake (dark with antibiotic)

Radiotracer doped incubation in the dark with antibiotic (>2µm size fraction)

SNPURYPF Size-fractionated normalised phosphorus uptake (dark with antibiotic)

Radiotracer doped incubation in the dark with antibiotic (0.2- 2µm size fraction)

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SNPURZPB Size-fractionated normalised phosphorus uptake (188 µE/m²/s with antibiotic)

SNPURZPF Size-fractionated normalised phosphorus uptake (188 µE/m²/s with antibiotic)

Radiotracer doped incubation at 188 µE/m²/s with antibiotic (0.2-2µm size fraction)

Originator Code Definitions

Belgica cruises BG9309, BG9322, BG9412, BG9506 and BG9521 10 Ir. Marc Elskens VUB, Brussels, Belgium

14 Dr. Lei Chou ULB, Brussels, Belgium 72 Prof. Roland Wollast ULB, Brussels, Belgium Belgica cruise BG9522

10 Ir. Marc Elskens VUB, Brussels, Belgium 72 Prof. Roland Wollast ULB, Brussels, Belgium Discovery cruise DI217

3 Dr. Ian Joint Plymouth Marine Laboratory

Originator Protocols

Ir. Marc Elskens

Labelled nitrate, urea and ammonia (99% ¹⁵N) were added to sea water samples in 2000 or 700 ml polycarbonate bottles. Tracer additions were kept as low as possible whilst still facilitating accurate measurements. Ambient levels were increased by 0.1 and 0.05 µM for nitrate and ammonia respectively.

Incubation conditions were 10-20 hours in constant light of 100 µE/m²/s on cruises BG9309, BG9322 and BG9412 and 188 µE/m²/s on cruises BG9506, BG9521 and BG9522. Incubator temperature was controlled by continuously flushing with surface sea water.

At the end of the incubation the samples were filtered (Whatman GF/F) and converted to nitrogen gas by a modified Dumas method. Isotope detection

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was carried out by emission spectrometry (Fiedler and Proksh, 1975) using either a Jasco NIA-1 or N-151 analyser. High-purity tank nitrogen gas was used as a working standard during sample analysis.

Dr. Lei Chou

Water samples were collected using water bottles deployed on a CTD rosette. 200 ml aliquots were doped with 11.9 µCi ¹⁴C and 20-30 (BG9309, BG9412, BG9521) or 3.2-12 (BG9322) µCi ³²P (as carrier-free H3

32PO4).

The spiked samples were then incubated for between 6 and 20 hours under one or more of the following conditions:

Constant light (100 µE/m²/s on cruises BG9309, BG9322 and BG9412: 188 µE/m²/s on cruises BG9506, BG9521)

Full sunlight Total darkness Azide poisoned

Constant light as above with antibiotic (10% polymyxin B sulphate, 10% streptomycin sulphate: 100 µl per 200ml sample)

Total darkness with above antibiotic

Note that a number of samples, some with antibiotic added, were incubated in constant light with bottles sandwiched between neutral density filters to give a light gradient. These data have not been parameterised into Pmax and alpha.

Consequently, they cannot be mapped into the BOTDATA structure and the data may be found with the other non-parameterised production profiles elsewhere in the database (tables C14HDR, C14DAT, P33HDR and P33DAT).

Temperature of incubation was controlled by a bath of pumped surface seawater. The incubation conditions for any data point may be determined from the parameter code.

At the end of the incubation the samples were filtered using GF/F or 2 micron and 0.2 micron Nuclepore filter cascade to obtain size-fractionated data. The filtration protocol may again be determined from the parameter code used.

Uptake rates were computed on the basis of the following ambient concentrations:

Cruise Station Depth(m) PO4(µM) TCO2(mM)

BG9309 GC10b 5 0.2 2.048

BG9309 GC10b 40 0.37 2.055

BG9309 GC11 5 0.07 2.091

BG9322 GC3 3 0.059 2.223

BG9322 GC5 3 0.032 2.071

BG9322 GC5 50 0.027

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Cruise Station Depth(m) PO4(µM) TCO2(mM)

BG9322 GC11 35 0.107 2.222

BG9412 OX01A 20 0.028 2.257

BG9412 OX02 20 0.167 2.261

BG9412 OX03 20 0.035 2.300

BG9412 OX04 20 0.402 2.309

BG9412 OX05 20 0.135 2.290

BG9412 OX06 20 0.436 2.293

BG9412 OX08 20 0.390 2.295

BG9412 OX15A 20 0.437 2.282

BG9412 OXHO 10 0.616 2.139

BG9412 OXCS 5 0.201

BG9412 OXCS 20 0.206

BG9412 OXCS 30 0.238

BG9412 OXCS 40 0.272

BG9412 OXCS 60 0.555

BG9412 OXCS 80 0.705

BG9506 OX01 20 0.255 2.018

BG9506 OX03 3 0.382 2.079

BG9506 OX03 20 0.389 2.077

BG9506 OX03 40 0.387 2.076

BG9506 OX04 20 0.395 2.075

BG9506 OX05 20 0.423 2.076

BG9506 OX06 20 0.425 2.077

Cruise Station Depth(m) PO4(µM) alkalinity(mEq/l)

BG9521 01A 3 0.041 2.309

BG9521 01A 20 0.014 2.312

BG9521 01A 45 0.790 2.312

BG9521 02A 3 0.011 2.312

BG9521 02A 20 0.005 2.311

BG9521 02A 35 0.377 2.316

BG9521 04A 3 0.027 2.331

BG9521 04A 40 0.041 2.332

BG9521 05C 3 0.081 2.318

BG9521 05C 20 0.104 2.316

BG9521 05C 35 0.099 2.319

BG9521 05C 60 0.162 2.319

BG9521 05C 75 0.162 2.317

BG9521 05E 30 0.100 2.319

BG9521 07A 3 0.050 2.335

BG9521 07A 40 0.079 2.334

BG9521 08A 3 0.072 2.347

BG9521 08A 40 0.168 2.323

BG9521 09A 3 0.043 2.331

BG9521 09A 20 0.040 2.332

BG9521 09A 40 0.058 2.331

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Cruise Station Depth(m) PO4(µM) alkalinity(mEq/l)

BG9521 10A 3 0.050 2.332

BG9521 10A 20 0.024 2.331

BG9521 10A 40 0.086 2.330

BG9521 11A 3 0.067 2.332

BG9521 11A 20 0.029 2.330

BG9521 11A 35 0.168 2.330

Note that the carbon uptake rates were supplied in units of µM/hour. These have been converted to mg/m³/hour by multiplying the data by 12.011.

Prof. Roland Wollast

Constant light incubations were at a light intensity of 100 µE/m²/s on cruises BG9309, BG9322, and BG9412. This was increased to 188 µE/m²/s on cruises BG9506, BG9521 and BG9522. Temperature was controlled by continuously circulating surface seawater. Samples were GF/F filtered at the end of the incubation.

Photosynthesis versus irradiance experiments were performed in either 200 or 600 ml culture bottles in an artificial light gradient from 0 to 800 µE/m²/s in a bath maintained at constant temperature by circulating surface seawater.

Incubation times were limited to 6-8 hours. The relationship between ¹⁴C uptake and light intensity has been parameterised following the model of Platt et al. (1980).

Data were supplied in either µM/hour or mg/m³/hour. Where necessary, the data have been standardised to the latter unity by multiplying by 12.011.

Dr. Ian Joint

Water samples were collected using GoFlo bottles deployed on the CTD rosette. Replicate samples were distributed into clear polycarbonate bottles and ¹⁵NO3 and ¹⁵NH4 were added. The concentrations of added isotope were kept as low as practicable (0.03 µM).

The samples were incubated for approximately 6 hours in an on-deck incubator at 97% ambient light at sea surface temperature.

The samples were filtered (<40cm Hg vacuum) through pre-ashed Whatman GF/F filters which were rinsed with filtered sea water and stored frozen until analysis back at the laboratory. The size-fractionated data were obtained by filtering through a 5 micron pore size polycarbonate filter placed over a GF/F filter in a filter cascade. The 5 micron filter was jettisoned and the GF/F filter analysed to give the GF/F to 5 micron size class.

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The thawed filters were oven-dried at 50 °C before analysis. Atomic percentage ¹⁵N was measured by continuous-flow nitrogen analysis mass spectrometry (Europa Scientific Ltd.) using the techniques described by Barrie et al. (1989) and Owens and Rees (1989). The rates of assimilation were calculated using the equations of Dugdale and Goering (1967).

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Metal Assimilation Rates

Parameter Code Definitions

CDRURAP2 Cadmium relative uptake rate (100 µE/m²/s)

Tracer doped constant light incubation 100 µE/m²/s (0.45 micron pore filtered)

Parts per thousand per hour

CDRURBP2 Cadmium relative uptake rate (188 µE/m²/s)

CDRURDP2 Cadmium relative uptake rate (dark)

Tracer doped incubation in the dark (0.45 micron pore filtered) Parts per thousand per hour

CORURAP2 Cobalt relative uptake rate (100 µE/m²/s)

CORURBP2 Cobalt relative uptake rate (188 µE/m²/s)

Parts per thousand per hour CORURDP2 Cobalt relative uptake rate (dark)

CSRURAP2 Caesium relative uptake rate (100 µE/m²/s)

MNRURAP2 Manganese relative uptake rate (100 µE/m²/s)

MNRURBP2 Manganese relative uptake rate (188 µE/m²/s)

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MNRURDP2 Manganese relative uptake rate (dark)

ZNRURAP2 Zinc relative uptake rate (100 µE/m²/s)

ZNRURBP2 Zinc relative uptake rate (188 µE/m²/s)

Parts per thousand per hour ZNRURDP2 Zinc relative uptake rate (dark)

Originator Code Definitions

Belgica cruises BG9412, BG9521 and BG9522

72 Professor Roland Wollast ULB, Brussels, Belgium

Originator Protocols

Professor Roland Wollast

Water samples were taken from GoFlo bottles and immediately spiked with

54Mn, ⁶⁰Co, ⁶⁵Zn, ¹⁰⁹Cd and (for a few of the stations) ¹³⁷Cs. The samples were incubated for 6-8 hours at a constant light level of 100 µE/m²/s (BG9412), 188 µE/m²/s (BG9521 and BG9522) or in darkness. Incubation temperature was controlled by continuously flushing with surface sea water.

After vacuum filtration on 0.45 micron membrane filters, the radioactivity of the filters and acidified filtrates was measured with an HPGe Camberra detector, with a relative efficiency of 20%, and a series 20, model 282 multichannel spectrometer. The minimum number of counts was fixed at 1000 to reduce the standard deviation to 3%.

To ensure that perturbation of the natural conditions was kept to a minimum, concentrations of the radionuclides and their carriers were maintained at a minimum level. The activity of the spike was usually approximately 100 nCi/l for each individual radionuclide. However, to obtain this level, the concentration of the corresponding dissolved metal was raised by 5-10 nM due to the presence of the carrier. In the area investigated, the ambient

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concentration of the trace metals considered was of the order of 0.02 nM for Co, 0.08 nM for Cd, 0.7 nM for Mn and 5 nM for Zn in the upper 100m of the water column. The increase in trace metal concentrations due to the addition of the tracers were therefore significant. For the 1995 field experiment (cruise BG9521 and BG9522), supplies of unsupported Mn and Cd radionuclides were obtained and used.

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Metal Distribution Coefficients

Parameter Code Definitions

CDKDRAX2 Cadmium fast distribution coefficient (100 µE/m²/s)

Radiotracer incubation at 100 µE/m²/s: phases split by 0.45 micron membrane filtration

Litres per kilogram

COKDRAX2 Cobalt fast distribution coefficient (100 µE/m²/s)

Litres per kilogram

CSKDRAX2 Caesium fast distribution coefficient (100 µE/m²/s)

Litres per kilogram

MNKDRAX2 Manganese fast distribution coefficient (100 µE/m²/s)

Litres per kilogram

ZNKDRAX2 Zinc fast distribution coefficient (100 µE/m²/s)

Litres per kilogram

Originator Code Definitions

72 Professor Roland Wollast ULB, Brussels, Belgium

Originator Protocols

Professor Roland Wollast

The Fast Distribution Coefficient, or KFDC (Mouchel and Martin, 1990), is defined as the ratio, found after the reaction time, of the particulate activity to the dissolved activity of the added radioisotope, normalised to the suspended matter concentration.

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Water samples were taken from GoFlo bottles and immediately spiked with

54Mn, ⁶⁰Co, ⁶⁵Zn, ¹⁰⁹Cd and (for a few of the stations) ¹³⁷Cs. The samples were incubated for 8 hours at a constant light level of 100 µE/m²/s (BG9412).

Incubation temperature was controlled by continuously flushing with surface sea water.

After vacuum filtration on 0.45 micron membrane filters, the radioactivity of the filters and acidified filtrates was measured with an HPGe Camberra detector, with a relative efficiency of 20%, and a series 20, model 282 multichannel spectrometer. The minimum number of counts was fixed at 1000 to reduce the standard deviation to 3%.

To ensure that perturbation of the natural conditions was kept to a minimum, concentrations of the radionuclides and their carriers were maintained at a minimum level. The activity of the spike was usually approximately 100 nCi/l for each individual radionuclide. However, to obtain this level, the concentration of the corresponding dissolved metal was raised by 5-10 nM due to the presence of the carrier. In the area investigated, the ambient concentration of the trace metals considered was of the order of 0.02 nM for Co, 0.08 nM for Cd, 0.7 nM for Mn and 5 nM for Zn in the upper 100m of the water column. The increase in trace metal concentrations due to the addition of the tracers were therefore significant.

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Bacterial Production, Abundance and Characteristics

Parameter Code Definitions

BATTMAPZ Proportion of total bacteria attached to particles

Epifluorescence microscopy with acridine orange stain Per cent

SDLERIP4 Standard deviation of leucine uptake rate

Isotope doped, incubated, filtered (0.2 µm pore filter) and counted

Picomoles/litre/hour

SDTBMDPZ Standard deviation of total bacteria Microscopy (DAPI stain)

Number per millilitre

SDTHRIP4 Standard deviation of thymidine uptake rate

TBBMMAPZ Total bacteria biomass as carbon

Calculated from cell counts determined by epifluorescence microscopy with acridine orange stain

Milligrams per cubic metre TBCCMAPZ Total bacteria cell numbers

Microscopy (acridine orange stain) Number per millilitre

TBCCMDPZ Total bacteria cell numbers Microscopy (DAPI stain) Number per millilitre

TBMSIAPZ Median size of total bacteria

Image analysis of acridine orange stained sample Micrometres (microns)

UPLERIP4 Leucine uptake rate

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UPTHRIP4 Thymidine uptake rate

Originator Code Definitions

Valdivia cruise VLD137 and Discovery cruise DI217

3 Dr. Ian Joint Plymouth Marine Laboratory, UK Pelagia cruises PLG93 and PLG95A

96 Dr. Laurenz Thomsen GEOMAR, Kiel, Germany

Originator Protocols

Dr. Ian Joint

Bacterial Production

Bacterial production was estimated from the rates of incorporation of [methyl-

3H] thymidine and of L-[4,5-H³] leucine (specific activities 79 Ci/mmol and 171 Ci/mmol respectively; Amersham International plc, UK). Leucine stocks were routinely diluted 1:3 with unlabelled leucine. Stock radiotracer solutions were prepared using sterilised glassware and stored in pharmaceutical-grade serum bottles that had been pre-treated by filling with 0.25 molar Analar grade HCl, left to stand for three days, rinsed with Milli-Q water, filled with Milli-Q water and left to stand for a further two days. Serum bottles and their Teflon-lined silicone seals were autoclaved before use. Stock radiotracer solutions were prepared in sterile, 0.2 micron filtered, Milli-Q water and stored at 2°C. A fresh stock bottle was used for each experiment.

Tritiated thymidine incorporation experiments followed the methods of Fuhrman and Azam (1982) and the leucine incorporation experiments followed the methods of Simon and Azam (1989), modified to include the cold trichloroacetic acid (TCA) extraction method of Chin-Leo and Kirchman (1988). Five replicate, 10 ml aliquots from each depth sampled were transferred to sterile, polystyrene, tissue-culture tubes and placed in an incubator in the dark, at in-situ temperatures and allowed to acclimatise for 15 minutes prior to the addition of the isotope. Electron microscope grade glutaraldehyde was added to one replicate sample from each depth at a final concentration of 2.5% by volume to act as controls. ³H-thymidine or ³H- leucine was added to each tube to give final concentrations of 5 and 10 nM respectively.

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The samples were incubated for one hour, but time-course assays showed that incorporation was linear for two hours and frequently longer.

At the end of the incubation, samples were transferred to an ice/water bath and ice-cold TCA added to give a final concentration of 5% by volume. The samples were left in the water bath for 15-30 minutes and filtered through 25mm 0.2 micron pore-size, track-etched, polycarbonate membrane filters.

Each filter was rinsed five times with 1ml 5% ice-cold TCA, placed in a scintillation vial and stored in a desiccator with active silica gel for 24 hours.

At the end of this period, the samples were counted in an LKB Rackbeta 1219 liquid scintillation counter. Counting efficiency was determined by an external standard, channels ratio method and checked by the occasional addition of internal standards.

Bacterial abundance

Samples were fixed with 2.5% by volume, 0.2 micron filtered, electron microscope grade glutaraldehyde, stained immediately with DAPI (4’6- diamidino-2-phenylindole) as described by Porter and Feig (1980) and filtered.

Samples were either examined immediately or stored frozen at -20 °C until examined back at the laboratory. Fluorescent bacteria were counted with an epifluorescence microscope by the method of Hobbie et al. (1977). The microscope used was a Leitz Ortholux II equipped with a 50W HBO light source, Ploempak 2.2 fluorescence vertical illuminator with filter block A and an NPL Fluorotar 100/1.32 oil objective lens.

Dr. Laurenz Thomsen

Water samples were collected using the BIOPROBE benthic water sampling lander (Thomsen et al., 1994). This was deployed on a conductor cable and gently positioned on the sea bed with approximately 20m of slack cable.

Penetration into the sediment was determined by a graduated rod monitored by a video camera.

After the material disturbed by the instrument deployment had been seen from transmissometer readings to have dispersed, water samples were collected by pumping into sample bottles on a command signal from the ship.

Sampling inlets were positioned at different heights on the instrument enabling water at different heights from the seabed to be collected. Further samples were collected with the lander raised at different heights, generally 5m or 50m, above the sea floor.

Bacterial cell numbers were determined by the acridine orange direct counting technique of Hobbie et al. (1977) using a Zeiss 'Standard' fluorescence microscope. Cell numbers were supplied in units of 10⁷ cells per litre and were converted to cells per millilitre by multiplying by 10,000.

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Bacteria size was estimated using a Macintosh Power PC image analysis system according to the method of Thomsen (1991). A carbon conversion factor of 0.4 picograms of carbon per cubic micrometre was used to determine biomass from cell counts. Further details of the protocol may be found in Thomsen and Graf (1995).

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Carbon and Nitrogen Isotopes

Parameter Code Definitions

D13CMITX Total inorganic carbon (TCO2) ¹³C enrichment (δ¹³C) Mass spectrometry on acid-liberated CO2

Parts per thousand

D13CMOPC Particulate organic carbon ¹³C enrichment (δ¹³C)

Mass spectrometry on acidified combusted sample (centrifuged) Parts per thousand

D15NMTPC Particulate total nitrogen (“PON”) ¹⁵N enrichment (δ¹⁵N) Mass spectrometry on combusted sample (centrifuged) Parts per thousand

Originator Code Definitions

Cruises Belgica 9309, 9322, 9412

10 Ir. Marc Elskens VUB, Brussels, Belgium 30 Dr. Patrick Dauby University of Liege, Belgium Cruise Meteor M27_1

73 Prof. Robin Keir GEOMAR, Kiel, Germany

Originator Protocols

Suspended particulate matter was collected by continuous flow centrifugation using an Alpha-Laval oil purifier (model MAB 104) specially coated for oceanographic use. Water supply was adjusted to approximately 1 cubic metre per hour. Samples were collected both when the ship was on station and steaming between stations for about 6-10 hours.

Samples were taken from the centrifuge body using a stainless steel spatula, stored in acid-washed PET vials and immediately deep frozen. After weighing (wet weight) the sample was subdivided for C/N, trace metal and isotope analysis.

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The samples for δ¹⁵N determination (~20 mg dry material) were decarbonated by acidification and the particulate nitrogen converted to dinitrogen by a modified Dumas method (Owens, 1987) using L-shaped quartz tubes. The tubes were attached to the inlet system of a Mass spectrometer Delta E Finnigan immersed in liquid nitrogen to trap carbon dioxide and water before analysis. Determinations of δ¹⁵N were undertaken using high purity nitrogen from a tank as the primary standard.

The data are expressed as:

δ¹⁵N = [(Rsample/Rstandard) - 1 ] * 1000

where R is the ¹⁵N/¹⁴N ratio. IAEA-N1 and IAEA-N2 reference materials were used as working standards. Final results are expressed relative to atmospheric nitrogen (Mariotti, 1983).

Dr. Patrick Dauby

Sub-samples for δ¹³C determination were decarbonated by acidification then oven dried at 55 °C. The material was ground into a fine powder and vacuum sealed in Pyrex tubes with copper oxide wire. These were heated at 550 °C for a day to complete combustion of the organic matter. The carbon dioxide generated was cryogenically trapped using liquid nitrogen. δ¹³C was determined either on a Varian Mat CH5 or Optima (Micromass) Isotope Ratio Mass Spectrometer, using certified CO2 gas (Messer Griesheim) as an intermediate standard. All values are reported relative to the international PDB standard as:

δ¹³C = [(Rsample/Rstandard) - 1] * 1000

where R is the ¹³C/¹²C ratio. Routine measurements were reported as accurate to within ±0.3 ppt.

Prof. Robin Keir

Water samples were drawn from the CTD rosette and returned to Kiel for analysis. The isotopic composition of the inorganic carbon was determined by

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acidifying with orthophosphoric acid. The CO2 liberated is stripped by high purity nitrogen and trapped in a loop immersed in liquid nitrogen under rough vacuum. The gas is separated from water vapour by distillation and trapping at controlled temperatures. The purified CO2 is then analysed using a Finnigan-MAT Delta E gas isotope mass spectrometer.

A manual sample processing line was used for the Meteor 27_1 samples. A number of samples were contaminated during analysis by isotopically light atmospheric CO2. The data from these were removed from the data set prior to submission to BODC.

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Dissolved and Colloidal Organic Carbon

Parameter Code Definitions

CORGNOD3 Dissolved organic carbon

High temperature Ni catalytic oxidation (GF/C filtered) Micromoles/litre

CORGCOC1 Colloidal organic carbon

Difference in Pt HTCO determined DOC between 0.4 µm and 10⁴ Dalton filtered samples

Micromoles/litre

CORGCOD1 Dissolved organic carbon

High temperature Pt catalytic oxidation (GF/F filtered) Micromoles/litre

CORGCOD2 Dissolved organic carbon

High temperature Pt catalytic oxidation (0.4 µm pore filtered) Micromoles/litre

CORGCOTX Total organic carbon

High temperature Pt catalytic oxidation (unfiltered) Micromoles/litre

SDOCCOD1 Dissolved organic carbon standard deviation

SEOCCOD1 Dissolved organic carbon standard error

SEOCCOTX Total organic carbon standard error

High temperature Pt catalytic oxidation (unfiltered) Micromoles/litre

Originator Code Definitions

Belgica Cruise BG9309

14 Dr. Lei Chou ULB, Brussels, Belgium

49 Dr. Jean-Marie Martin Institut de Biogeochimie, France

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Belgica Cruise BG9322

14 Dr. Lei Chou ULB, Brussels, Belgium Meteor Cruises M27_1 and M30_1

9 Mr. Thomas Raabe Hamburg University, Germany 51 Prof. Wolfgang Balzer University of Bremen, Germany Valdivia Cruise VLD137

9 Mr. Thomas Raabe Hamburg University, Germany Charles Darwin Cruises CD84 and CD94

13 Dr. Axel Miller Plymouth Marine Laboratory, UK.

Originator Protocols

Dr. Lei Chou

Water samples were collected using either 10 l acid-cleaned polypropylene bottles deployed manually or Niskin/GoFlo bottles deployed on a CTD rosette.

Water bottle samples were filtered using pre-ashed (450 °C) GF/F filters. 10 ml samples were transferred into 15 ml glass ampoules which were poisoned with 100 µl of 1 g/l HgCl2 and sealed.

Back at the laboratory the samples were assayed using a Shimadzu TOC- 5000 analyser.

Dr. Jean-Marie Martin

Water samples were collected using either 10 l acid-cleaned polypropylene bottles deployed manually or Teflon lined GoFlo bottles deployed on a CTD rosette. The samples were filtered under nitrogen pressure through acid- cleaned 0.4 micron Nuclepore filters. 1-2 litres were passed through the filter and discarded to guard against adsorption and/or release of organic carbon from the filter.

A 50ml sample was poisoned with HgCl2 for DOC analysis. Filtered water was then passed through a cross-flow ultra-filtration (CFF) system with a polysulphate membrane (10⁴ Daltons) to separate colloids from the truly dissolved fraction. Quadruplate samples were collected when the concentration factor was around 4-6. All filtration was conducted using ultra- clean techniques under laminar-flow clean benches.

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DOC was determined on the filtrate and ultra-filtrate by high temperature catalytic oxidation using a Shimadzu TOC-5000 analyser. Samples were injected into a furnace at 680 °C onto a catalyst made of 1.2% Pt coated SiO2. The CO2 produced was measured by a non-dispersive infra-red (NDIR) detector. The instrument and water blanks were evaluated for each set of sample analysis as described by Cauwet (1994).

Mr. Thomas Raabe

Water samples were taken from the CTD rosette and filtered through Whatman GF/C filters. The filtrate was poisoned with mercuric chloride and stored in glass and polythene bottles in a cooling chamber until analysed.

Samples were analysed by high temperature catalytic oxidation using a nickel catalyst.

Prof. Wolfgang Balzer

Water samples were taken from the CTD rosette and filtered under ultra- clean conditions through pre-combusted GF/F filters. The filtrate was then acidified, sealed in brown glass ampoules and stored at 4 °C until analysed.

Samples were analysed by high temperature catalytic oxidation. Samples were analysed in triplicate.

Dr. Axel Miller

Samples were taken from the CTD rosette and generally filtered through GF/F filters, although some samples in low particulate waters were analysed unfiltered to assess filtration as a source of contamination. Ultra-clean handling techniques were used throughout.

The analytical technique involves the direct injection of acidified and decarbonated sea water onto a platinised alumina catalyst at high temperature (680-900 °C) under an atmosphere of oxygen or high purity air.

Quantitative production of CO2 gas allows DOC concentrations to be determined using a CO2-specific infrared gas analyser (IRGA).

Analyses were undertaken at sea using a Shimadzu TOC-5000 HTCO analyser fitted with a LiCor Li6252 IRGA. This overcame the problems associated with using the standard TOC-5000 IRGA on an unstable platform.

Great care was taken to quantify blank signals generated at all stages of the analytical procedure and to correct the data for them.

A more detailed description of the protocols followed may be found in Miller et al. (1993).

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Comments on Data Quality

Belgica 9309

The ULB data set contains a number of high values of up to nearly 6000 µM.

Of particular concern are the data from the upper 300m from station 11 which jump from 138 µM at 400m to 2403 µM at 300m and some of the data from the Zodiac transects. The IBM data from station 11 (but a different cast) give values of 1-200 µM in the upper 200m and their values for most samples from the rias are significantly lower than the ULB data.

The ULB values from the upper 300m of station 11 have been flagged suspect, together with samples from the rias in excess of 400 µM. The possibility of contamination of some samples has been suggested by the data originator as the cause of the problem. Values in the range 200-400 µM have been left unflagged but users should bear in mind that they may also be contaminated to some extent.

Meteor 27_1 and 30_1

The bulk of the water samples was analysed for DOC by both Bremen and Hamburg universities. The Hamburg data are systematically 2-3 times higher than the Bremen data. The cause of this is unknown. The Bremen data exhibit excellent agreement with the PML data collected on cruise Charles Darwin 84 which went to sea the day after Meteor 27_1 docked.

The Hamburg data set included 6 samples from Meteor 27_1, usually from rosette position 1, which showed exceptionally high DOC values. These have been flagged suspect. Three unusually high values (5-10 times the Bremen value) from Meteor 30_1 have also been flagged suspect.

Valdivia 137

The DOC values from this cruise are systematically higher than those obtained by other groups working in the OMEX project. On the two Meteor cruises, Hamburg and Bremen determined DOC on the same samples. The Hamburg results were consistently 2-3 times higher than the Bremen data.

A small number of data points from VLD137 are extremely high, with the odd sample exceeding 2000 µM. Values in excess of 400 µM have been flagged suspect.

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Dissolved Total Nitrogen and Phosphorus

(from which Dissolved Organic Nitrogen and Phosphorus may be Determined)

Parameter Code Definitions

NTOTCOD1 Dissolved total nitrogen

NTOTWCD3 Dissolved total nitrogen

Oxidation then autoanalysis (GF/C filtered) Micromoles/litre

SETNCOD1 Dissolved total nitrogen standard error

TPHSWCD3 Dissolved total phosphorus

Originator Code Definitions

Meteor cruises M27_1 and M30_1, Valdivia cruise VLD137 and Discovery cruise DI217

9 Mr. Thomas Raabe Hamburg University, Germany Charles Darwin Cruise CD94

13 Dr. Axel Miller Plymouth Marine Laboratory, UK 9 Mr. Thomas Raabe Hamburg University, Germany

Originator Protocols

Water samples were taken from the CTD rosette and filtered through Whatman GF/C filters. The filtrate was poisoned with mercuric chloride and stored in glass and polythene bottles in a cooling chamber until analysed.

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The samples were oxidised by peroxodisulphate in an autoclave (Eberlein and Kattner, 1987) followed by nitrate/phosphate determination.

Dr. Axel Miller

Samples were taken from the CTD rosette or surface sea water supply and filtered through GF/F filters. Ultra-clean handling techniques were used throughout.

The analytical technique involves the direct injection of acidified and decarbonated sea water onto a platinised alumina catalyst at high temperature (680-900 °C) under an atmosphere of oxygen or high purity air.

Quantitative production of the nitric oxide radical allows total dissolved nitrogen concentrations to be determined using a nitrogen-specific chemiluminescence detector.

Analyses were undertaken at sea using a Shimadzu TOC-5000 HTCO analyser fitted with an Antek 705-D chemiluminescence detector. The combustion products travelled through a Drierite trap (97% CaSO4, 3%

CoCl3) and a membrane (permeation tube) drier to remove any trace of water.

The dried nitric acid radical was then reacted with ozone to produce the excited chemiluminescent nitrogen species and passed to the detector. Each sample was injected four times with each injection cycle taking 5.5 minutes.

Great care was taken to quantify blank signals generated at all stages of the analytical procedure and to correct the data for them.

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Particulate Organic Carbon, Inorganic Carbon, Nitrogen, Phosphorus and Silica

Parameter Code Definitions

CINGWLP1 Particulate inorganic carbon

Weight loss on acidification (GF/F filtered) Micromoles/litre

CORGCAP1 Particulate organic carbon (acidified)

Acid fumed then C/N analyser (GF/F filtered) Micromoles/litre

CORGCAP4 Particulate organic carbon (acidified)

Acid fumed then C/N analyser (30 µm pore filtered) Micromoles/litre

CORGCNP3 Particulate organic carbon (unacidified) Carbon/nitrogen analyser (GF/C filtered) Micromoles/litre

ICCNCNP2 Inorganic carbon content (filtered SPM)

Difference between C/N analyser results on total and acidified samples (0.4/0.45 µm pore filtered)

Per cent

ICCNCNPC Inorganic carbon content (centrifuged SPM)

Difference between C/N analyser results on total and acidified samples (centrifuged)

Per cent

NTOTCNP1 Particulate total nitrogen (“PON”)

Carbon/nitrogen analyser (GF/F filtered) Micromoles/litre

Carbon/nitrogen analyser (30 µm pore filtered) Micromoles/litre

Carbon/nitrogen analyser (GF/C filtered) Micromoles/litre

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OCCNCAP1 Organic carbon content (GF/F filtered SPM)

Acidification then carbon/nitrogen analyser (GF/F filtered) Per cent

OCCNCAP2 Organic carbon content (0.45 micron pore filtered SPM) Acidification then carbon/nitrogen analyser (0.4/0.45 µm pore filtered)

Per cent

OCCNCAPC Organic carbon content (centrifuged SPM)

Acidification then carbon/nitrogen analyser (centrifuged) Per cent

OPALWCP7 Particulate opaline silica

NaOH hydrolysis of material trapped on a cellulose acetate filter Micromoles/litre

TNCNCNP2 Total nitrogen content (0.45 micron pore filtered SPM) Carbon/nitrogen analyser (0.4/0.45 µm pore filtered) Per cent

TNCNCNPC Total nitrogen content (centrifuged SPM) Carbon/nitrogen analyser (centrifuged) Per cent

TPHSWCP3 Particulate total phosphorus

Originator Code Definitions

10 Ir. Marc Elskens VUB, Brussels, Belgium 14 Dr. Lei Chou ULB, Brussels, Belgium 30 Dr. Patrick Dauby University of Liege, Belgium Belgica cruise BG9506

10 Ir. Marc Elskens VUB, Brussels, Belgium 14 Dr. Lei Chou ULB, Brussels, Belgium Belgica cruises BG9521 and BG9522

10 Ir. Marc Elskens VUB, Brussels, Belgium

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Charles Darwin cruise CD84

14 Dr. Lei Chou ULB, Brussels, Belgium Meteor cruises M27_1 and M30_1

9 Mr. Thomas Raabe Hamburg University, Germany 96 Dr. Laurenz Thomsen GEOMAR, Kiel, Germany Charles Darwin cruise CD94 and Valdivia cruise VLD137

9 Mr. Thomas Raabe Hamburg University, Germany

Pelagia cruises PLG93 and PLG95A and Charles Darwin cruise CD86

96 Dr. Laurenz Thomsen GEOMAR, Kiel, Germany Charles Darwin cruise CD85

7 Dr. Avan Antia University of Kiel, Germany Discovery cruise DI217

7 Dr. Avan Antia University of Kiel, Germany 9 Mr. Thomas Raabe Hamburg University, Germany Jan Mayen cruises JM1-JM11

61 Dr. Paul Wassmann University of Tromsø, Norway Charles Darwin cruise CD83

39 Mr. Bob Head Plymouth Marine Laboratory, UK

Auriga cruises PLUTUR2-PLUTUR5 and Andromeda cruise PLUTUR6 91 Dr. Aurora Rodrigues Instituto Hidrografico, Portugal

Originator Protocols

Sea water samples from Niskin or GoFlo bottles were filtered on pre- combusted Whatman GF/F filters. The filters were air dried at 60 °C and kept at room temperature until analysed. The samples were treated with HCl vapour to remove carbonates and analysed using a Carlo Erba NA1500 elemental analyser. The CO2 and N2 were separated by means of a gas

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chromatographic column (Poropak QS) and measured by thermal conductivity detection.

Dr. Lei Chou

Samples were obtained using one of two protocols. The protocol used may be identified by the gear code in the EVENT entry for the data (SAP or GPCENT).

SAP collection

Challenger Oceanics in-situ stand-alone pumps (SAPs) were used to sample particulate material. The instruments are operated by a programmable timer to ensure that the pump only operates when in position at the desired depth.

Membrane filters with a 0.4 micron pore size were used to collect the particulate material.

On recovery the filters were rinsed and dried in clean conditions.

GPCENT collection.

If sufficient material was available, a sample for carbon and nitrogen determination was acidified to remove carbonates and then assayed in an Interscience NA-2000 elemental particulate analyser.

Inorganic carbon content was determined where sufficient material was available by analysing both acidified and unacidified samples and computing the difference.

Dr. Patrick Dauby

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Back in the laboratory, sub-samples were dried and weighed, slightly acidified to remove carbonates, rinsed, oven dried and ground into a fine powder. Determinations of C and N were performed with a Carlo Erba NA1500 elemental analyser.

The data were supplied to BODC in the form of organic carbon content in parts per thousand and molar C/N ratio. The units were converted to percentages and the nitrogen contents computed from the molar ratio assuming atomic weights for carbon and nitrogen of 12.011 and 14.007 respectively.

Water samples taken from the CTD rosette were filtered through Whatman GF/C filters and kept at -17 °C until analysed back at the laboratory using a high combustion CHN-analyser.

Phosphorus was determined by persulphate digestion followed by determination as orthophosphate using the methods of Kattner and Brockmann (1980).

Dr. Avan Antia

Water samples were taken from either the bottles on the CTD rosette or from large (30 litre) GoFlo bottles deployed from the hydrographic winch. Aliquots were filtered through GF/F filters for carbon determinations and cellulose acetate filters for biogenic silica determinations. Inorganic carbon was measured gravimetrically through weight loss on acidification. Organic carbon was determined on samples with the inorganic carbon removed using a CHN analyser. Biogenic silica was determined by wet chemical methods after hydrolysis of the sample.

The data were supplied in various units. For Charles Darwin CD85, organic carbon was supplied in units of µg/l. This was converted to µM through division by 12.011.

For Discovery DI217, organic carbon was supplied in mg/l and inorganic carbon was supplied in mg/l of CaCO3. Inorganic carbon in µM was computed by multiplying the CaCO3 value by 1000 then dividing by 100.0892.

The organic carbon was converted by multiplying by 1000 and dividing by 12.011.

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Dr. Paul Wassmann

Water samples were taken from the CTD rosette and filtered through pre- combusted Whatman GF/F filters and analysed on a Leeman lab CHN analyser after removal of carbonate.

The data were supplied in units of µg/l. Carbon and nitrogen were converted to µM by dividing by 12.011 and 14.007 respectively.

Mr. Bob Head

Replicate 500 ml aliquots were taken from CTD rosette bottles or the underway non-toxic sea water supply. After an initial screening through a 200 micron mesh, to prevent spurious results caused by large zooplankton, the samples were filtered through 25mm GF/F filters. Additional aliquots were taken on some stations and filtered through 30 micron pore filters to give additional data for the >30 micron size fraction. Samples were frozen at -20

°C until analysed back at the laboratory.

The samples were acidified with sulphur dioxide to remove carbonates and then dried at 50 °C for 2 days. The samples were then encapsulated in squares of pre-combusted aluminium foil in a 4.5mm press.

The samples were analysed in a Carlo Erba NA1500 elemental analyser at a reactor temperature of 1030 °C and a helium carrier flow rate of 120 ml per minute. Calibration was effected with standards of acetanilide assayed on a calibrated Cahn 25 balance. Filter and sea water blanks were analysed and used to correct the data.

Dr. Aurora Rodrigues

Water samples were collected using a portable pump and filtered through Whatman GF/F filters. Organic carbon was determined at the University of Bordeaux using the method of Strickland and Parsons (1972) as adapted by Etcheber (1982). Samples were treated with 2N HCl to remove carbonates and assayed using a LECO CS-125 analyser.

The POC values were supplied in units of µg/l and converted to µM by dividing by 12.011.

Dr. Laurenz Thomsen

Water samples were collected using the BIOPROBE benthic water sampling lander (Thomsen et al., 1994). This was deployed on a conductor cable and gently positioned on the sea bed with approximately 20m of slack cable.

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Penetration into the sediment was determined by a graduated rod monitored by a video camera.

After the material disturbed by the instrument deployment had been seen from transmissometer readings to have dispersed, water samples were collected by pumping into sample bottles on a command signal from the ship.

Sampling inlets were positioned at different heights on the instrument enabling water at different heights from the seabed to be collected. Further samples were collected with the lander raised at different heights, generally 5m or 50m, above the sea floor.

The water samples were filtered on GF/F filters, acidified to remove carbonates and analysed using a Heraeus CHN analyser. Further details of the protocol are given in Thomsen and Graf (1995).

Comments on Data Quality

Belgica Cruises

Comparison of the carbon and nitrogen contents between the centrifuged samples and shallow SAP samples was possible at two stations. The values compared well.

Both ULB and Liege determined organic carbon and total nitrogen content on the centrifuged samples. An intercalibration of the two data sets by BODC showed excellent agreement. Regressing one data set against the other gave the following results:

Carbon ULB = 1.0051 * Liege + 0.7038 (R² = 92%; n=37) Nitrogen ULB = 1.0062 * Liege + 0.225 (R² = 90%; n=34)

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Nutrients

Parameter Code Definitions

AMONAAD2 Dissolved ammonium

Colorometric autoanalysis (0.4/0.45 µm pore filtered) Micromoles/litre

AMONAATX Dissolved ammonium

Colorometric autoanalysis (unfiltered) Micromoles/litre

AMONMATX Ammonium (unfiltered)

Manual colorometric analysis (unfiltered) Micromoles/litre

NTRIAAD2 Dissolved nitrite

NTRIAAD5 Dissolved nitrite

Colorometric autoanalysis (0.2 µm pore filtered) Micromoles/litre

NTRIAATX Nitrite (unfiltered)

NTRZAAD2 Dissolved nitrate + nitrite

NTRZAAD5 Dissolved nitrate + nitrite

NTRZAATX Nitrate + nitrite (unfiltered)

PHOSAAD2 Dissolved phosphate

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PHOSAAD5 Dissolved phosphate

PHOSAATX Phosphate (unfiltered)

PHOSMATX Phosphate (unfiltered)

SLCAAAD2 Dissolved silicate

SLCAAAD5 Dissolved silicate

SLCAAATX Silicate (unfiltered)

SLCAMATX Silicate (unfiltered)

UREAMDTX Urea (unfiltered)

Manual analysis using the diacetylmonoxime method Micromoles/litre

Originator Code Definitions

Belgica cruise BG9309

10 Ir. Marc Elskens VUB, Brussels, Belgium 14 Dr. Lei Chou ULB, Brussels, Belgium 66 Dr. Ricardo Prego IIM, CSIC, Vigo, Spain

Belgica cruises BG9322, BG9412, BG9506, BG9521 and BG9522 10 Ir. Marc Elskens VUB, Brussels, Belgium

14 Dr. Lei Chou ULB, Brussels, Belgium